1. Field
Disclosed embodiments are related to active suspension systems and the control algorithms thereof.
2. Discussion of Related Art
An active suspension system is a key enabler for the modern passenger vehicle to set it apart from other vehicles. Energy consumption of these systems is becoming a more difficult hurdle to overcome. As the world strives to be more environmentally friendly, consumers are becoming more and more conscious of energy consumption, and vehicles are becoming increasingly efficient in several aspects of their operation, from shutting down the engine at stop lights, to regenerating braking energy, to using hybrid engine approaches, to better aerodynamics.
One of the last frontiers in this domain is suspension systems, where the drive for more performance has often led to higher energy consumption. The present invention fits in that domain by providing a more energy-efficient approach to an active suspension system.
Many automakers have tried to produce a true high-bandwidth active system and failed due to several key shortcomings of existing approaches. One of the most important shortcomings of these systems is their generally unacceptably high power consumption. One of the key functions of any suspension system, be it for a vehicle, machine, platform, or other device, is to isolate the motion of the device or vehicle from its environment (in the case of the vehicle, the road). When the vehicle drives over rough road, or the base of the platform moves, energy is imparted into the suspension through the relative motion of the two components with respect to each other. If not dissipated, this energy may create unwanted motion in the device. Removing energy from a driving vehicle means that the energy efficiency of the vehicle decreases (since all energy in this case is coming from the vehicle itself). The less energy dissipated in the suspension, the more efficient the vehicle can be. At the same time, the comfort to the occupants and stability of the vehicle are also important factors influenced by the suspension system. This poses a dilemma in active suspension systems, since high power consumption in an active suspension drastically increases the integration challenge.
For this reason, active and semi-active suspension system designers are conscious of power consumption, and the control algorithms used in such systems are often conceived seeking to minimize power consumption and yet provide desirable performance. Existing systems deal with this in many different ways. Most systems are designed with power efficiency in mind, in order to provide the same performance at the lowest possible power output. Some systems have control algorithms designed to limit total power consumption, or that balance regeneration (where existing) with consumption. Parameters in the algorithm are also sometimes adapted to the road conditions in order to provide the best performance. A need exists for improved systems.